linux-kernel - [PATCH 04/13] f2fs: fix to clear dirty inode in error path of f2fs

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Message-ID: <20190415072842.2438-4-yuchao0@huawei.com>
Date:   Mon, 15 Apr 2019 15:28:33 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     <jaegeuk@...nel.org>
CC:     <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>, <chao@...nel.org>,
        Chao Yu <yuchao0@...wei.com>
Subject: [PATCH 04/13] f2fs: fix to clear dirty inode in error path of f2fs_iget()

As Jungyeon reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=203217

- Overview
When mounting the attached crafted image and running program, I got this error.
Additionally, it hangs on sync after running the program.

The image is intentionally fuzzed from a normal f2fs image for testing and I enabled option CONFIG_F2FS_CHECK_FS on.

- Reproduces
cc poc_test_05.c
mkdir test
mount -t f2fs tmp.img test
sudo ./a.out
sync

- Messages
 kernel BUG at fs/f2fs/inode.c:707!
 RIP: 0010:f2fs_evict_inode+0x33f/0x3a0
 Call Trace:
  evict+0xba/0x180
  f2fs_iget+0x598/0xdf0
  f2fs_lookup+0x136/0x320
  __lookup_slow+0x92/0x140
  lookup_slow+0x30/0x50
  walk_component+0x1c1/0x350
  path_lookupat+0x62/0x200
  filename_lookup+0xb3/0x1a0
  do_readlinkat+0x56/0x110
  __x64_sys_readlink+0x16/0x20
  do_syscall_64+0x43/0xf0
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

During inode loading, __recover_inline_status() can recovery inode status
and set inode dirty, once we failed in following process, it will fail
the check in f2fs_evict_inode, result in trigger BUG_ON().

Let's clear dirty inode in error path of f2fs_iget() to avoid panic.

Signed-off-by: Chao Yu <yuchao0@...wei.com>
---
 fs/f2fs/inode.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 06233375c129..03a354d5e6ab 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -489,6 +489,7 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
 	return inode;
 
 bad_inode:
+	f2fs_inode_synced(inode);
 	iget_failed(inode);
 	trace_f2fs_iget_exit(inode, ret);
 	return ERR_PTR(ret);
-- 
2.18.0.rc1